Investigation of the new technique of ion microscopy is proposed for direct elemental and isotopic histochemical analysis of soft and hard tissues. The parameters affecting quantitative ion probe analysis will be investigated to provide reliable quantitative data on specific microfeatures in cytology. This information will be used in the development of a system for quantitative image analysis which will be applied to both feature and field chemical analysis of tissue sections. Elemental distribution will be correlated with morphology using light and electron microscopy. Concurrent with the investigation of the technique, the ion microscope will be applied to a number of biological and medical problems on a collaborative basis.